Cytoplasmic dynein is the main minus-end directed motor protein to walk along microtubules inside cells, but the complex structure has made dynein difficult to purify and study in vitro. This study aims to purify dynein and label the motors with fluorophores or beads to probe their stalling force, step size, and processivity. Dynein coated beads will be grabbed by optical tweezers to detect steps and forces. Single fluorescent dyneins can be accurately located as they walk along microtubules using total internal reflection fluorescence microscopy and fluorescence imaging with one nanometer accuracy to determine the step size and processivity. This work will not only reveal the inner workings of the dynein motor protein, but will also further inform us of dynein malfunction related to motor neuron diseases.